Leaky faucets, while not as serious a problem as leaky toilets, can waste a significant amount of water. Faucets typically leak because of old gaskets or O-rings and corroded valve seats. The single most common mistake in faucet repair is not taking along the faucet/parts when buying the replacement parts.
Before working on any faucet turn the water off and open the lines to drain the water out. Cover the sink with a towel to protect it from tools that might drop and to prevent small parts from falling into the drain. Wrap the jaws of wrenches with tape to protect the finish of the faucet.
When you disassemble a faucet, pay close attention to the order of the parts, it’s easy to forget the correct order. You might even sketch, or photograph the parts laying in sequence. Some typical faucet layouts are shown here. Follow manufacturer directions for installing the new parts.
If you have less water flow when you turn the water back on after a plumbing repair, rust is probably clogging a valve. Old steel pipes (especially hot water lines) rust on the inside. When you turn the water back on, rust scales break loose and lodge in the valves. To clear them out, open them to full flow. Also unscrew the faucet aerators and rinse them clean.
Today, most faucets can be categorized as being “washerless” (port-type faucets), or compression (washer). Note: A washerless faucet does not mean it will never leak! Rather the parts will last longer since their design minimizes friction and wear. When repairing this type of faucet or requesting service on one, it is vital that you know the brand name, or have a sample of the part you require.
How to Replace a Washer
To replace a washer, first turn off the water supply line. Next, take the faucet apart and throw away the old washer. The most important thing about the new washer is it’s size. The washer has to fit around the valve stem, spreading out to the edges, when it is screwed down.
When you’ve got the right size washer, put it in the old washer’s place and reassemble the faucet. If the drip is still there, something else might be wrong and you may need to contact a plumber.
If you own a faucet with a single lever, or joystick, the disassembly and repair is still relatively simple, but different from the valve stem and washer type. If you need help, a good hardware or plumbing supply store will have the necessary replacement parts and can probably direct you to a good instruction source.
If, after all this detective work, your water meter still indicates that you have a leak, the problem could be in under-ground pipes. You may need to call a plumber.
Leaky Supply Tubing
When the line, or tubing, that supplies water to a faucet or toilet leaks, it’s best to go ahead and replace the tubing. Note: Make sure to get the right size fittings for each end of the tubing. The difference between one size/type and another is subtle. Take your old supply tube/fittings with you and ask a clerk to select a proper length replacement with compatible fittings.
Be prepared to replace the shutoff valve as well as the tubing. Old valves that no one has turned for years may spring a leak when suddenly turned. First, you’ll have to shut off the main valve to your house. Then use a wrench or pliers to unscrew the old valve from the nipple in the wall. Place a bucket under the pipe and have someone turn the water on briefly to flush rust from the pipe. If the old nipple is damaged and recessed too far in the wall to get a pipe wrench on it, try an internal pipe wrench to save your plaster. Buy a replacement valve with female thread to screw onto the nipple. Wrap the nipple with Teflon tape, and then screw on the new valve with an adjustable wrench. Be sure to point the valve outlet toward the fixture as you finish the last turn. Turn the main valve back on and test for leaks.
CUWCC Practical Plumbing Handbook